When President Obama meets with the president of China tomorrow, he will have his National Security adviser at his side. Tom Donilon set the stage for this summit during a trip to Beijing last week. Now he's stepping down.

NPR's Scott Horsley has this look at his legacy and the woman Obama has tapped to replace him.

SCOTT HORSLEY, BYLINE: Tom Donilon keeps a relatively low profile in Washington. He rarely shows up on the evening news. But Donilon has been a fixture at the White House ever since President Obama moved in.

PRESIDENT BARACK OBAMA: Nearly every day, for the past several years, I've started each morning with Tom leading the presidential daily brief; hundreds of times, a sweeping assessment of global developments and the most pressing challenges.

HORSLEY: Yesterday, members of the National Security Council filled the White House Rose Garden to hear the president announce Donilon will be giving up his 24/7 responsibilities next month. Donilon stood alongside Obama, blinking in the afternoon sunshine.

TOM DONILON: You mentioned the many hours we've worked together in the Situation Room, without windows.

OBAMA: No windows.

DONILON: No windows. So I would first like to thank you for this rare opportunity to be outside and experiencing natural light.

(LAUGHTER)

HORSLEY: Obama says despite the almost daily crises in the Situation Room, Donilon was also able to keep his eye on more long-term goals, most notably the administration's renewed focus on Asia, with its fast-growing economies that Obama felt had been neglected by previous presidents.

Editor-at-large David Rothkopf of Foreign Policy magazine says that strategic thinking will be a big part of Donilon's legacy.

DAVID ROTHKOPF: The White House can very easily get trapped in the news cycle and find itself scrambling, reacting to headlines, reacting to yesterday's events, worried about what's going to happen tomorrow. Donilon worked regularly to look at what the longer-term issues were going to be for the United States.

HORSLEY: Rothkopf, who also wrote a history of the National Security Council, says Donilon added to the size and influence of the NSC. But despite that highly-centralized White House operation, which can breed resentment elsewhere, Donilon also reached out to the Pentagon, the State Department, and the CIA.

ROTHKOPF: Which can be a little bit like herding cats and a little bit like lion taming at times, you know, because you've got a lot of big egos, a lot of different agencies with a lot of different agendas.

HORSLEY: Donilon won the trust of the president in part by keeping his own ego in check.

OBAMA: I think that Tom Donilon has been one of the most effective national security advisers our country has ever had, and he's done so without a lot of fanfare and a lot of fuss.

HORSLEY: The president's choice to replace Donilon, on the other hand, has generated both fanfare and fuss. Susan Rice, the U.S. ambassador to the United Nations, became a lightning rod for Republicans last year, after she went on television to describe the attack that killed four Americans in Benghazi, Libya. Rice was using talking points from the intelligence community that turned out to be wrong.

White House emails show Rice herself played little role in drafting those talking points. Nevertheless, GOP opposition forced her to drop out of the running for the secretary of State's job.

Rice has been a longtime supporter of Obama, though, adding much needed foreign policy credibility during his first campaign for the White House. Obama has tried to repay that loyalty. Yesterday he called Rice a consummate public servant.

OBAMA: She is fearless. She is tough. She has a great tennis game and a pretty good basketball game.

(LAUGHTER)

OBAMA: Her brother's here, who I play with occasionally. And it runs in the family, throwing the occasional elbow...

(LAUGHTER)

OBAMA: ...but hitting the big shot.

HORSLEY: Republican Senator John McCain said he disagreed with Rice's appointment but added he'd make every effort to work with her. For her part, Rice said she looks forward to working with leaders in both parties.

SUSAN RICE: We have much still to accomplish on behalf of the American people, to keep our nation strong and safe.

HORSLEY: The president's choice of a national security adviser is not subject to Senate confirmation.